Water acts so strangely in space astronauts can use it as a ping pong ball

Water behaves in some pretty bizarre ways 250 miles above Earth in microgravity.

On Jan. 21, astronaut Scott Kelly celebrated his 300th day aboard the International Space Station by demonstrating one of the many strange things water can do in space: it can double as a ping pong ball. 

First Kelly carefully squeezed out a water droplet from the packets of water that astronauts use for drinking, cleaning, and bathing. Water molecules love to stick to each other, and without gravity acting on them, they clump into the shape with the least amount of surface area — a sphere. 

Then he used two paddles with a water-repellent Teflon coating to gently tap the droplet back and forth.

Big drops are easy to accidentally burst — a problem when those droplets can float off into unsuspecting machinery lining the space station's walls — but small drops like this one can survive harder hits.

Of course, this kind of slow-motion ping pong game would not be very exciting to watch. Each player would have plenty of time to line up their shot.

SEE ALSO: Here’s how astronauts exercise in space

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